When Nazi Germany invaded Poland, they incorporated Lodz into the Greater German Reich. They renamed the city Litzmannstadt in honour of a German general, Karl Litzmann, who had led German forces in the area in 1914.

The Lodz Ghetto was the second largest WWII ghetto for Jews and Roma in German-occupied Poland. Over 180, 000 people were crowded into an area of 4.13 kilometers. in Baluty and the Old Town area. It was the most impoverished part of the city. The ghetto was officially sealed off from the rest of the city on May 1, 1940.